Jared Sullinger was at a loss to explain how the Celtics could win while committing a season-high 28 turnovers.

‘‘I honestly don’t know,’’ he said.

Try this: 20 points, nine assists and seven rebounds by Rajon Rondo, a 62-37 rebounding advantage by the Celtics and a horrible 4-for-30 shooting performance on 3-pointers by the Nets.

The result was a 91-84 victory in which Brooklyn never led and had its four-game winning streak stopped Friday night.

The rebounding ‘‘was obviously the difference in the game for us, from our standpoint. That, and they missed the 3s,’’ Boston coach Brad Stevens said. ‘‘I'd like to say that it was this outstanding 3-point defense, but I think when you re-watch it, it’s a lot of open 3s they missed.’’

The Celtics scored the first five points and won for just the second time in nine games. And they held off Brooklyn after an 11-point run cut the lead to 70-68 with 2:02 left in the third quarter. The Celtics came back to take a 78-70 lead entering the final quarter and led by at least seven points the rest of the way.

‘‘We shared the ball pretty well with our team, and theirs,’’ Stevens said after watching the Celtics commit twice as many turnovers as Brooklyn, ‘‘so, overall, it was at least a step in the right direction.’’

The Nets were led by Joe Johnson with 21 points and Deron Williams with 20 as they fell back to .500 two days after going over the mark for the first time this season.

The Celtics (21-41) were coming off a very poor performance in a 108-88 loss to Golden State on Wednesday night.

Jason Collins, the NBA’s first openly gay player, did not play for the Nets for the first time in seven games since signing a 10-day contract Feb. 23. Collins, who played for the Celtics last season, signed a second 10-day contract Wednesday.

The Celtics got 15 points from Jeff Green and 14 from Jerryd Bayless. Sullinger led all rebounders with 12. But Rondo was the key, despite his seven turnovers.

Rondo missed the first 40 games recovering from offseason knee surgery and has shown an improved shooting touch recently. He hit three of six 3-pointers Friday.

‘‘He did a tremendous job coming into the season working on his jumper constantly,’’ Sullinger said. ‘‘Now he’s starting to become the Rondo we all know every day.’’

Paul Pierce scored 10 points in his second appearance in Boston since the blockbuster trade that sent him and Kevin Garnett to the Nets in the offseason. Pierce spent 15 seasons with the Celtics after they drafted him with the 10th pick in 1998.

He received light applause when he was introduced with the other Nets starters. Garnett missed his fourth straight game with back spasms.

‘‘Every time I come into this gym, it’s going to be emotion. Not like last time, though,’’ Pierce said. ‘‘We just didn’t have any rhythm on offense or defense.’’

Pierce and Garnett each scored six points in their first game in Boston this season, an 85-79 Brooklyn win Jan. 26. Both were emotional during and after video tributes on the video screen above center court.

On Friday, the Celtics led 53-41 at halftime — after the Nets missed all 17 of their 3-pointers — and 70-57 with four minutes left in the third quarter.

Brooklyn scored the next 11 points with Shaun Livingston starting the spurt with two free throws and Andray Blatche following with a 3-pointer. Andrei Kirilenko made a three-point play, Marcus Thornton sank a layup and Johnson hit a free throw.

Green ended the run with a three-point play, the Celtics led 78-70 entering the fourth quarter and stayed ahead by at least seven the rest of the way.